• In a mixing bowl, whisk together flour, baking powder and salt. Set aside until ready to use.
• In the bowl of a stand mixer fitted with a paddle attachment, beat the butter on medium-high speed for 1-2 minutes. Alternatively, use a large mixing bowl and a handheld mixer. Add the sugar and beat on medium-high speed once again until light and fluffy, about 3 minutes. Scrape down the sides of the bowl and mix briefly once again. 
• Add the egg and mix on medium speed until well-incorporated. Add the half and half, along with both the vanilla and almond extract and mix once more.
• Add the flour in 3 separate additions, mixing on low after each addition. Do not over-mix. Divide the dough into two rounds and lay each atop a sheet of plastic wrap. Flatten into a disk shape, wrap and refrigerate until chilled, no less than 1 hour. The dough can be made a day in advance.
• Preheat the oven to 350° and have ready cookie sheets lined with either parchment paper or a Silpat.
• One at a time, lay the disks atop a large floured work surface. Lightly flour each side of the dough round. Begin rolling, from the middle outward in each direction, shifting the dough slightly after each roll to avoid sticking. Do this until the dough is a ¼” in thickness. Cut out dough into desired shapes.
• Transfer the cookies to the prepared cookie sheets, spacing them at least 1 inch apart. Bake until the outer edges are just tinged with golden-brown, about 8-10 minutes. Remove from the oven and allow to cool completely before icing.

For the Royal Icing:

• Have ready a piping bag fitted with a round tip.
• In the bowl of a stand mixer, combine powdered sugar, meringue powder, water and extract. Begin mixing on low until powdered sugar has absorbed the liquid ingredients, then increase speed to high. Alternatively, use a large mixing bowl and a handheld mixer. Mix for 2-3 minutes or until the icing is the consistency similar to toothpaste.
• To ensure the icing is the right consistency, test it by allowing icing to drip from the paddle attachment or beaters. It should take about 30 seconds before the fallen icing loses its shape and melds into the rest of the icing.
• If coloring the icing, add the food coloring now. 
• To apply the icing to the cookie, pipe a line of icing about an eighth of an inch from the edge of the cookie. This is also called outlining. Do not pipe directly on the edge. Then, pipe in a tight and compact zig-zag pattern to fill the inside of the cookie. This is also called flooding.
• Decorate with sprinkles and decals while the icing is still wet. Set aside and allow to set for at least 4 hours, but preferably overnight.